Myasthenia gravis

Definition

• A autoimmune disorder of the motor endplate that is associated with thymomas and causes a syndrome of weakness that worsens with repeated movements
• Can also present with predominantly bulbar involvement, or simple ocular involvement

Clinical Presentation

• History
• Signs & Symptoms
  • Ptosis worse than baseline
  • Abnormal or fatiguable extraocular movements
  • Dysarthria
  • Neck flexion and extension (tests C3-4 that also innervates the diaphragm)
  • Decreased duration of limb raiding

Management

• Acute
  • Monitor FVC, MIPS, and MEPS
    • Can approximate FVC by counting the duration of exhilation
• Chronic